Various embodiments described herein relate generally to fabrication of assemblies where a number of layers are deposited on a substrate and a number of lines are scribed in the layers, and more particularly to methods and related systems for fabricating assemblies by sequencing the deposition of layers and the scribing of lines so as to enhance throughput. These methods and related systems may be particularly effective for laser scribing thin-film single junction and multi junction solar cells.
An existing fabrication sequence used for forming thin-film solar cells involves depositing or otherwise forming a plurality of layers on a substrate, such as a glass, metal or polymer substrate suitable to form one or more p-n junctions. An example thin-film solar cell includes a transparent-conductive-oxide (TCO) layer, a plurality of doped and undoped silicon layers, and a metal back layer. A series of laser-scribed lines can be used to create individual cells connected in series. Examples of materials that can be used to form solar cells, along with methods and apparatus for forming the cells, are described, for example, in U.S. Pat. No. 7,582,515, issued Sep. 1, 2009, entitled “MULTI-JUNCTION SOLAR CELLS AND METHODS AND APPARATUSES FOR FORMING THE SAME,” which is hereby incorporated herein by reference.
FIGS. 1A through 1E illustrate an existing fabrication sequence for a thin-film solar-cell assembly where a number of layers are deposited on a substrate and a series of lines are laser scribed within the layers to delineate individual cells. FIG. 1A illustrates the first step in the existing fabrication sequence, where a TCO layer 12 is deposited on a glass substrate 10. FIG. 1B illustrates the second step, where a first set of lines 14, 16 (herein referred to as “P1” interconnect lines and “P1” isolation lines, respectively) are laser scribed in the TCO layer 12. FIG. 1C illustrates the third step, where a plurality of doped and undoped amorphous silicon (a-Si) layers 18 are deposited on top of the TCO layer 12 and within the scribed P1 lines 14, 16. FIG. 1D illustrates the fourth step, where a second set of lines 20 (“P2” lines) are laser scribed in the silicon layers 18. FIG. 1E illustrates the fifth step, where a metal layer 22 is deposited on top of the silicon layers 18 and within the scribed P2 lines 20. FIG. 1E also illustrates the sixth step, where a third set of lines 24, 26 (“P3” interconnect lines and “P3” isolation lines, respectively) are laser scribed as illustrated.
The fabrication of such an assembly contributes to total cost of a solar cell. While other factors beyond cost of production (e.g., quality of an item produced, overhead costs, etc.) are important considerations, lower production costs are desirable. Accordingly, it is desirable to develop improved methods and related systems having reduced production costs for fabricating solar panels. Additionally, such a need for improved methods and related systems may also exist for other manufacturing processes involving the deposition of layers and the scribing of lines within the layers.